Flexible pouch fitment structure

ABSTRACT

A flexible plastic fitment for providing spouts for pouches formed of sheet material. The fitment includes a pair of opposed side walls each having a center portion formed from diametrically opposed segments of a common cylinder and straight segments that blend respectively into the cylindrical segments on opposite sides of the common cylinder. The side walls are joined together at both ends thereof to form a canoe shape. A cover, which provides the only support for the side walls joins the top edges of the canoe shape and extends at both ends of the canoe shape between the cylindrical segments and the joined ends. A thin fin extends from each end of the joined side walls. A method of and apparatus for attaching the fitment by distending the side walls outwardly while urging the sheet material toward the side walls is also disclosed.

BACKGROUND OF THE INVENTION

The present invention relates to fitments and in particular to a spoutfitment for a flexible package.

Fitments are often used to provide a pouring spout for containers formedof flexible films. It has heretofore been proposed to use afitment/spout with a canoe-shaped base that serves to provide a smooth,gradual transition between the plies of film from which the package isto be formed and the pouring spout which is coaxial with the center ofthe fitment. Common wisdom taught that the fitment canoe section shouldbe relatively rigid so as not to misshape the center spout section whenthe fitment is subjected to the heat and pressure needed to seal thepackage film to the fitment. This, in turn, required that the sealingjaws as well as the fitments be precisely sized to assure the formationof tight seals. Frequently it is necessary to attach the fitment withone set of sealing jaws and then seal the pouch film with a seconddifferent set of jaws. Unfortunately, in practice, fitments injectionmolded of polyethylene, polypropylene and the like often vary somewhatdimensionally during manufacture. Also, in time, the sealing jaws wearand such wear may not be uniform. As a result, during such packagemanufacturing, unreliable welds result and there is a failure to obtainconsistent packages. This is counterproductive to the desired productionrates for the packages formed utilizing such fitment attachmentprocesses.

The attachment of such fitment is disclosed in U.S. patent applicationSer. No. 09/452,714 entitled “Method for Attaching Fitment atLongitudinal Fin Seal and Package Resulting Therefrom” filed on Dec. 2,1999. A thin wall fitment is disclosed in U.S. patent application Ser.No. 09/643,033 filed Aug. 21, 2000 entitled “Thin Wall Fitment forSpouted Pouch”. Other prior art includes U.S. Pat. No. 5,911,340entitled “Spout Assembly, Spout Assembly Manufacturing Apparatus andPackage with Spout Assembly” issued on Jun. 15, 1999 to Uematsu; U.S.Pat. No. 5,716,471 entitled “Method for Securing Articles to Laminates”issued on Feb. 10, 1998 to Pape; U.S. Pat. No. 4,909,434 entitled“Moisture Impervious Carton Having One-Piece Pouring Spout Sealed toInnermost and Outermost Surfaces” issued on Mar. 20, 1990 to Jones etal.; U.S. Pat. No. 3,894,381 entitled “Method and Means for AttachingFitments to a Bag or Pouch on a Packaging Machine” issued on Jul. 15,1975 to Christine et al.; and U.S. Pat. No. 5,855,544 entitled “FlexibleContainer With Tubular Fitment And Method And Apparatus For AssemblingSame” issued on Jan. 5, 1999 to Buchanan.

OBJECTS AND SUMMARY OF THE INVENTION

It is a principal object of the present invention to provide an improvedfitment with canoe-shaped walls which can be installed at relativelyhigh speeds with a single set of sealing jaws.

A further object is to provide such a fitment wherein the canoe-shapedwalls are designed to distort during the installation process so as tofacilitate and enhance sealing of the associated package film to thefitment side walls.

A still further object is to provide a method of and apparatus forsealing a fitment to a package film that ensures the formation of tightseals between the fitment and package film.

The above and other beneficial objects and advantages are attained inaccordance with the present invention by providing a flexible plasticfitment. The fitment includes side walls having a center portioncomprising diametrically opposed segments of a common cylinder andstraight segments that blend respectively into the cylindrical segmentson opposite sides of the common cylinder and are joined together at bothends thereof in a pointed tip thereby forming a canoe shape. A coverjoins the top edges of the canoe shape and extends at both ends of thecanoe shape between the cylindrical segments and the pointed tip. A thinfin at each end of said joined side walls, said fins comprisingextensions of said pointed tips.

The fitment is attached to an associated film package by inserting thefitment between facing sheets of the film forming the package,substantially aligned with edges of the facing sheets. Prior to that amandrel is inserted into the center of the common cylinder of thefitment. The mandrel may be dimensioned to distend the fitment sidewalls' cylindrical segments and straight segments outwardly which causesaccurate positioning of these surfaces. While the mandrel is positionedwithin the common cylinder and distending the cylindrical segments andstraight segments of the side walls outwardly, heated sealing jaws closeto capture the film sheet edges against the fitment to seal the filmedges to the side walls. In this regard, the sealing jaws includesconvex sections out-of-line with the mandrel which urge the packagingfilm inwardly as the sealing jaws close to thereby enhance the contactof the fitment and packaging film and thereby compensate for anydimensional intolerance.

It is usually desirable to simultaneously contact the package film, thussealing the film surface at the top of the pouch at the same time asattaching the fitment.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a perspective view of a fitment in accordance with the presentinvention;

FIG. 2 is a perspective view of the fitment of FIG. 1 in position to besealed between sheets of a packaging film, for clarity, the top sealingjaw has been partially removed;

FIG. 3 is a bottom (viewed from the fitment) plan view of the fitment ofFIG. 1 in position to be sealed to packaging film, for clarity, thebottom sealing jaw has been partially removed; and

FIG. 4 is a perspective view of a package formed by the sealingequipment of FIG. 2 utilizing the fitment of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is now made to the drawings and to FIG. 4 in particularwherein a package 10 is depicted. The package is formed of two sheets ofa suitable film for the contents to be held. In this regard, the filmmay be a laminate, the layers of which have desired barrier or otherproperties for the product to be contained and an appropriate sealantlayer for bonding to each other and to the fitment. The sheets aresealed to each other in a zone 12 extending about the package periphery,thereby forming a leak proof inner area 14 into which the packagecontents are captured. A spout 16 extends from the package top to theinner area 14. The spout 16 conveniently includes a center cylindricalneck 18 which carries external threads 20 for an associated cap. Thespout 16 is formed using a fitment 22 as shown in FIG. 1. Fitment 22 isconveniently injection molded of a thermoplastic material such aspolyethylene or polypropylene and the canoe section is relatively thin,on the order of 26-28 mils.

Fitment 22 comprises a cylindrical neck 18 which extends upwardly from acanoe-shaped base 24. The canoe-shaped base 24 consists of side walls26, 28 each of which is formed of a curved center portion 30, 32 intowhich straight segments 34, 36 and 38, 40 tangentially blend. The sidewalls 26 and 28 are joined at both ends at a point from which a thin fin42, 44 extends. It is important to note that there are no internal ribsor gussets supporting the side walls and that the only support comesfrom cover sections 46, 48 (see FIG. 2 and FIG. 3) at the top of thecanoe. As a result the fitment side walls are quite flexible andresilient. To facilitate attaching the fitment to the packaging film aseries of raised horizontal ribs 50 extend about the side walls from endto end. Because of the relatively low mass of the ribs 50, they readilyfuse with the packaging film when the heated sealing jaws are activated.The speed of the fusing is further assisted by the mass of the canoeside walls 26, 28, 34, 36, 38 and 40 acting as a heat sink to encouragerapid solidification of the ribs as the jaws open. A flange 52 extendsradially outwardly from cylindrical neck 18 between the canoe side wallsand the area of cap threads 20 of the cylindrical neck. The flange 52serves to facilitate feeding the fitment for attachment to the packagingfilm and accordingly is designed to properly orient the fitment duringthe attachment process.

Reference is now made to FIG. 2 wherein the sealing jaws 54, 56 andmandrel 58 of the sealing apparatus used to join the fitment 22 to thesheets of packaging film 60, 62 are depicted. It should be appreciatedthat for clarity only the bottom sealing jaw 54 and bottom film 60 areshown in detail. The top sealing jaw 56, which is identical to thebottom sealing jaw 54, but inverted, and top film 62, are cut away. Itwill also be appreciated that the mandrel 58 is oblong and oversized. Asa result, when the mandrel is inserted into the fitment 22 the sidewalls 26, 28 are stretched over the mandrel surface providing highlycontrolled and accurate positioning of that portion of the canoe base.It should be further noted that sealing jaws 54, 56 which have matingsections 72 that are generally contoured to receive the fitment, alsohave convex sections 64, 66, such convex sections will contact theunsupported sections of the canoe (38, 40) driving heat and pressureinto said portions of the canoe until the sealing jaws 54, 56 areclamped on the melting fins 42, 44. As the fins melt away the pouch filmsurface is pressurized and the top of the pouch is sealed. This resultsin a highly controlled and predictable relationship which consistentlyproduces a secure seal being formed between the fitment and thepackaging sheets even if there are minor dimensional variations or otherdistortions in the fitment. The sealing jaws 54, 56 further include flatsections 68, 70 on opposite sides of section 72 that is contoured toreceive the fitment. When the sealing jaws close, the flat sections 68,70 seal together the top edges of the packaging film on both sides ofthe fitment to form the top 74 of the package 14 while simultaneouslysecuring the fitment to the package. In this connection, the fins 42, 44at the ends of the canoe serve to permit a smooth transition between thesheet sealing and fitment sealing by the jaws. To further facilitatesealing of the film sheets the mandrel may be heated.

Thus, in accordance with the above, the aforementioned objects areeffectively attained.

1-7. (canceled)
 8. The method of securing a fitment to a packageincluding the steps of: providing two facing sheets of packagingmaterial; inserting a mandrel into a fitment so as to distend saidfitment cylindrical segments and inserting a fitment between said facingsheets substantially aligned with edges of said facing sheets, saidfitment having side walls formed of diametrically opposed segments of acommon cylinder and straight segments blended respectively into saidcommon cylinder segments, said side walls being joined together at bothends thereof thereby forming a canoe shape; sealing said facing sheetedges to said side walls while said fitment cylindrical segments areoutwardly distended by said mandrel.
 9. The method in accordance withclaim 8 wherein said facing sheet edges are sealed to said fitmentcylindrical segments by opposed sealing jaws closing toward each otherfrom opposite sides of said mandrel.
 10. The method in accordance withclaim 9 wherein said sealing jaws each include a section generallycontoured to include convex portions which are designed to engage andseal the resilient portions of the canoe walls outside of thecylindrical area.
 11. The method in accordance with claim 10 whereinsaid mandrel is heated.
 12. In combination for the sealing of a fitmentbetween facing packaging sheets, said fitment having side walls formedof diametrically opposed segments of a common cylinder and straightsegments blended respectively into said common cylinder segments, saidside walls being joined together at both ends thereof thereby forming acanoe shape: a mandrel for insertion between said side walls, saidmandrel being dimensioned to distend said fitment side walls outwardly;and opposed sealing jaws adapted to close toward each other fromopposite sides of said mandrel, said sealing jaws having contouredsections to urge said facing sheets toward said fitment when saidsealing jaws are closed.
 13. The combination in accordance with claim 12wherein said sealing jaws' contoured sections each include convexsections out-of-line with said mandrel when said jaws are closed, saidsealing jaws' convex sections urging said facing sheets toward saidfitment as said sealing jaws close.
 14. The combination in accordancewith claim 13 further comprising flat sections of said sealing jaws onopposite sides of said contoured sections.